There is a variety of hollow (concrete) building blocks known, some of which with insulating material in the cavities within. The cavities disclosed differ greatly in size, orientation, position, distribution, number and shape. However, none of the offered solutions to the problem of providing a structurally sound block with great insulating properties, satisfy the current regulations. The following are attempts of the prior art to provide a structurally sound, thermally insulating building block.
In EP 2,598,706 a technique is described for producing an insulated block by placing the insulating panels in the mold before filling the mold with mortar between the insulating panels. Furthermore, a type of block is disclosed wherein the front face of the block and the back face of the block are made of mortar. The front and back face are separated by insulating panels. This greatly improves the insulating properties of these blocks. However, the separating insulating panel can be subject to horizontal deformation across the thickness of the block, as insulating materials are generally far less resistant to pressure than the surrounding building materials. This can cause the blocks to be ‘compressed’ or ‘stretched’ horizontally when dealing with great forces and/or pressures. Furthermore, the block proposed in the application does not provide enough strength to be used in the structural support of a construction, unless produced exceedingly thick which will take more building space. This is an unwanted feature when dealing with situations with limited space such as apartments. In addition, the existing block lacks a provision to enable continuity of longitudinal reinforcement throughout the block, such as a rebar.
The invention proposed by said document would have the rebar run through the insulating material, which is not a valid option, as the weaker insulating material would be easily damaged by the rebar. Alternatively this would require an inner layer of mortar to provide a through-hole for the rebar, inside of the insulating panels. This is an impractical solution as it leaves the inner layer of mortar surrounded by insulating material. Again, such a construction will take a lot of space, which is a very unwanted consequence.
U.S. Pat. No. 5,904,963 discloses a block with a plurality of webs defining empty inner cavities with insulating properties. The latter cavities can be filled with insulating material, however air-filled cavities are preferred according to the document. Furthermore, the method to produce blocks of this type is highly impractical, as the web of inner cavities would have very thin walls. A block of this type could only efficiently be made up to a limited height due to viscosity problems when filling the block form, for instance with concrete. This would provide a reduced height compared to other types of blocks, which would allow for new paths for heat transfer through the block laying material (mortar for instance) connecting the separate blocks, thus nullifying much of the advantages in thermal insulation by the bricks. Lastly, no mention is made in the text on the implementation of further supporting materials to allow continuation of longitudinal reinforcement, such as a rebar, into this design.
US 2008/0184650 and US 2001/0022057 both disclose insulating blocks wherein thermal paths through block material are lengthened by the positioning of the cross webbing connecting an intermediate panel of block material to the front and back face. However, the document does not adequately provide a through-hole for rebar, as this would need to be placed in one of the cavities and in order to securely connect it with the insulating block, the entire cavity would need to be filled with a block material such as cement or concrete to ensure a strong interconnection. In doing so, this greatly reduces the insulating characteristics of the block however and makes the block more expensive and heavy due to the unnecessarily high amount of block material. Also, during fabrication of the blocks, the insulation is placed in the block afterwards, which typically will create a gap between the block material and the insulation, in which air is present. Here, a convective air flow can take place which partly negates the advantages of the insulation. Furthermore, and perhaps most importantly, when using the insulating block to build a wall, typically a staggered pattern is used to build the layers. In the case of the proposed block, providing rebar in the cavity of a first layer would mean this rebar runs through an indentation in an above lying layer. However, as this would mean the entrenchment of the rebar in connecting block material there, a direct thermally conducting path would be created via the cross webbings and the entrenching or connecting block material (outer element 110 in US 2008/0184650 or element 16 or 14 in US 2001/0022057). Furthermore, the blocks of the two mentioned documents do not provide an adequate solution for incorporating rebar into their structure, and do not allow an obvious adaptation in order for rebar to be possible, while maintaining high thermal insulation.
In DE 30 11 764 A1 a block is disclosed with non-linear thermal paths from the front face to the back face of the block. However, there is no possibility for the incorporation of rebar, and furthermore, the volume percentage of block material is too high to make this block economically relevant. Lastly, the production of said block would be impractical due to the high amount of thin spaces with insulating material and thin zones of block material.
In EP 0 209 993 A2 a composite block is proposed wherein two separate blocks sandwich a plate of insulating material and are tied together by at least one strap. It would be highly dangerous to use such blocks in construction due to unreliability of the strap considering the conditions in which the block is used, and by using what in fact are two separate blocks, the strength of the composite block is reduced significantly. Lastly, WO 2009/013289 provides a method and machine for producing blocks as mentioned in some of the documents in the general background.
WO 2009/013289 A2 provides a method with which building blocks can be produced, but however fails to achieve in providing a suitable block that is both highly thermally insulating and strong enough to be used in construction, as is achieved by the applicant.
A possible solution for the problems regarding thermal insulation and strength is offered in the form of so-called Thermoblocks® from Marmox. These use extruded polystyrene or polyisocyanurate as a layer of insulating material, but provide strength to the structure by placing pillars of polymer concrete into the layer of insulating material. Polymer concrete provides better thermal insulation than regular concrete, and still provides the strength necessary to ensure the structural stability of the block as a whole. However, even though polymer concrete is a much better thermal insulator than regular concrete or other commonly used materials, it is still far less insulating than ‘real’ insulating materials. Therefore, by having a multitude of these pillars as is the case in a Thermoblock®, the overall thermal resistance still does not adequately accommodate the needs of the industry. However, a major disadvantage of this solution is that polymer concrete is far more expensive than the commonly used materials for this purpose, and will provide a user a significantly more expensive product. Therefore, the product does not really offer a solution to the problem of providing an economically efficient, thermally insulating block capable of supporting loads. Also, no continuation of longitudinal reinforcement can be provided. As such, when referring to embodiments of the prior art, the Thermoblock® are not included as Thermoblock® fails to meet the goal of the invention of this document in an entirely different way than the previous embodiments, primarily in economic feasibility. Furthermore, Thermoblock® are notably hard to manipulate and process further.
There remains a need in the art for an improved insulated block that is financially interesting, easy to produce and practical to handle, possesses great structural strength and outstanding insulating characteristics and by staying compact, this without sacrificing living space.
The present invention aims to resolve at least some of the problems mentioned above.
The invention thereto aims to provide a structurally high performing, strongly thermally insulating block, which can be easily processed and manipulated (weight, dimensions and other). Furthermore, the invention provides a method for producing said block. Note that thermal insulation both from front face to back face is desired, but also from side face to side face.